This photo shows the MSR TrailShot water filter near a river.
Chris Maxcer

MSR TrailShot Water Filter Review

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The MSR TrailShot is a remarkably versatile lightweight water filter for backpacking, trail running, hiking, fishing, hunting, camping, kayaking and pretty much any outdoor adventure that might lead to thirst near a water source.

To get us a closer look, MSR sent Man Makes Fire a review unit of its Trail Base Water Filter Kit, the core of which is a slightly modified MSR TrailShot, which is so good on its own that it warrants a dedicated review. This is what we learned about the MSR TrailShot:

The MSR TrailShot Review

This photo shows the MSR TrailShot water filter on some rocks near a river.
The MSR TrailShot weighs just 5 ounces but can filter a liter of water in just 60 seconds.

The MSR TrailShot is the core filter component for the MSR Trail Base Water Filter Kit, which includes two bags for a gravity filter option (read our review for more detail).

As you might imagine, the TrailShot version in the MSR Trail Base Water Filter Kit is slightly modified to work with the gravity filter bags. There are two minor differences. First, the pre-filter at the end of the hose is threaded to attach to a dirty water bag while the standard TrailShot is not threaded. Second, the outgoing clean water spot on the kit version has a rubber o-ring so it can securely attach to the clean water bag in the kit. The non-kit TrailShot version has a smooth end.

The rest of the two units are the same — same size, same filter, same hand pumping action.

MSR TrailShot: Ultralight Speed

This photo shows the TrailShot portion of the MSR Trail Base Water Filter Kit held over a river.
Simply squeeze the TrailShot repeatedly to filter a liter in 60 seconds.

The key to the TrailShot is its ultralight 5 oz construction that nonetheless manages to filter up to a liter of water in 60 seconds, making it competitive with many more traditional hand-pump water filter designs.

The start of the filtration process starts with a pre-filter screen at the end of the hose, which is about 15 inches long. This end goes into your stream or lake water source. To pump, you simply squeeze the rubbery bulb repeatedly to suck water into the chamber and force it through the filter and out the nozzle.

When I first tried it, I was surprised at how easy and fast it was to prime the bulb and start filtering water. My biggest concern was being able to aim the nozzle at an angle to get it into a Nalgene water bottle, but it wasn’t all that difficult. I was even able to shoot water into much smaller water bottle openings with relative ease. I would occasionally miss, of course, but I wouldn’t say it was hard.

MSR TrailShot Review: Pros and Cons

There are a couple upsides and downsides to the overall design. First, the weight is about half that of larger, two-hand pump filters, which makes the TrailShot great to carry. Second, the length of hose lets you bend down and shoot water directly into your mouth, filtering it from the water source. Lightweight straw filters, like the LifeStraw, usually require you to lay down in the dirt or mud near a water source to drink — or pack a cup to use your filter straw with.

This photo shows the MSR TrailShot.
The MSR TrailShot is a near-perfect balance between an ultralight filter straw and a traditional filter pump.

On the other hand, the short length of hose on the TrailShot can make it difficult to pump water from hard to get to water sources — lakes and streams are easy, but if a water source is brushed in or sunken, it could be tough to reach, pump and fill your bottle at the same time. Heavier two-hand water filter systems like the MSR MiniWorks EX Microfilter usually have longer tubes to work with.

In terms of overall volume, you can filter up to 2,000 liters or so of water before potentially needing to replace the filter in the TrailShot.

To get the best filtration experience along the way to 2,000 liters, once the filter starts to get clogged — by doing its job — the TrailShot can become harder to squeeze and maintain water flow volume. This is a challenge for most every filter system, but two-handed pump systems are easier to power through. With the TrailShot, you’ll have a better experience if you clear out the filter every so often with a simple trick:

After filling your water bottles, before you put the TrailShot away, make sure the bulb reservoir is at least half full of water and detach the tube, holding your thumb over the entry hole. Vigorously shake the TrailShot for 10-to-30 seconds or so. You might see the water inside the translucent bulb look dirty — that’s great. Remove your thumb, let the dirty water pour out, reattach the tube and hit the trail.

Of course, what makes the TrailShot easy to pump with one hand also could be a con for some users: Your hand might get tired if you need to fill a lot of water bottles. As it turns out, MSR has a solution for that scenario, which is the aforementioned kit — read our full review: MSR Trail Base Water Filter Kit Review for more detail.

MSR TrailShot Effectiveness

This photo shows the MSR Trail Base Water Filter Kit.
You can buy the MSR TrailShot separately or get a slightly modified version with the MSR Trail Base Water Filter Kit.

The MSR TrailShot is effective in filtering out large particulates as well as bacteria (99.9999%) and protozoa (99.9%). That means that for most every freshwater source in North America, you’re good to go with the MSR TrailShot.

For international travel with truly sketchy water sources, you should know that the TrailShot does not filter out viruses. For virus filtration, you would need the top-of-the-line MSR Guardian Purifier or need to pack along extra chemical purification tablets or an alternative UV sterilizer.

All-in-all, the MSR TrailShot is one of the best ultralight water filters available today. If you tend to go backpacking with your family or in larger groups, the MSR Trail Base Water Filter Kit will offer you extra versatility, but if you’re looking for a fast-and-and ultralight water filter that’s also surprisingly versatile, the TrailShot is our favorite choice. Plus, as far as we’re concerned, the MSR TrailShot is must-have gear for any outdoor adventurer. Very highly recommended.

Get the Gear:

MSR TrailShot

Check shipping/pricing: Amazon | Cabela’s | CampSaver | Moosejaw | REI

MSR Trail Base Water Filter Kit
MSR MiniWorks EX Microfilter
MSR Guardian Purifier
Aquatabs

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